At Al-Taqwa mosque in Egypt's second biggest city, a preacher defends his ultra-orthodox Salafi group's decision to endorse Abdel Moneim Abouel Fotouh, an Islamist who casts himself as a moderate, in this month's presidential election.

"Don't consider his media statements only. He has various writings that confirm his comprehensive understanding of Islam and his desire to achieve it," Yasser Borhamy, a founder of the Salafi movement in Egypt, tells his Alexandria audience, his message recorded and posted on the group's website.

The poll, expected to go to a run-off in June, is a landmark in a turbulent transition to democracy that could see Egypt elect an Islamist to replace deposed President Hosni Mubarak, who repressed proponents of political Islam throughout his 30-year rule and battled armed Muslim militants in the 1990s.

The endorsement by Borhamy's influential Salafi Dawah and its political party, Nour, has pushed Abouel Fotouh towards the front of the pack and undercut Mohamed Morsy, the candidate of the rival Muslim Brotherhood.

But it has divided Salafis, who number as many as 3 million devotees plus other sympathizers among Egypt's 82 million people. Their votes could help swing the 23-24 May election.